Wallboard for backing wall tile blocks



April 1967 D. G. HAMME WALLBOARD FOR BACKING WALL TILE BLOCKS Filed Aug. 1, 1962 INVENTOR. G. HAMME DONALD ATTORNEYS United States Patent 3,312,585 WALLBOARD FOR BACKING WALL TILE BLOCKS Donald G. Hamme, Tonawanda, N.Y., assignor to National Gypsum Company, Buffalo, N. a corporation of Delaware Filed Aug. 1, 1962, Ser. No. 214,064 4 Claims. (Cl. 161-104) The present invention relates to the field of wall construction and is concerned particularly with wall construction in areas where the finished Wall surface is frequently contacted by water such as in bathtub enclosures and shower stalls.

The walls of bathtub enclosures, shower stalls and the like, are subject to the impingement of water, sometimes forceful as when discharged from the shower head. If the finished Wall surface is provided by tile blocks and the base therefor is damageable by extended contact with water, the base will gradually deteriorate. Sometimes such a deteriorated wall defies repair or correction short of reconstructing the same, at least in part.

In connection with the technique of dry wall construction commonly used in residential homes today, many prior attempts to provide a suitable means for adapting conventional paper-covered gypsum core wallboard as a base for wall tile blocks such as in bathrooms around bathtubs and in shower stalls, have included painting the base wall after erection with water-proofing paints, coating it with asphalt or covering the wall with a separate first coating of a water-proof adhesive which is allowed to dry before applying the tile adhesive proper. These practices have failed to provide a consistent, reliable way of resisting the normal tendency for water seepage behind the tiles. Of course, gypsum wallboard without any attempted water-proofing treatment is completely unsatisfactory, since access of water to the gypsum wallboard base rapidly destroys the integrity of the base and consequently results in eventual complete failure of the tile wall structure.

The present invention is intended to overcome these defects and has for its primary object the provision of an improved wallboard which is water impervious and may therefore be used as the base for wall tile blocks.

Another object is to provide such a wall tile backerboard for use in a dry wall construction.

A further object is to provide such a Wall tile backerboard having reliable and consistent water resistant characteristics.

A still further object is the provision of such a wall tile backerboard which is readily adaptable to a wide variation in desired structural and dimensional form for the wall area to be protected with a water impervious base, Without detriment to the water resistant characteristics.

Another object is to provide a water impervious wallboard which may employ the economies and strength of gypsum wallboard.

Another object of the present invention is to provide a novel wall structure particularly for use in areas repeatedly subject to the damaging effects of water.

Another aim of the invention is to provide a novel method of constructing a tiled wall including the base for the tile blocks, again particularly for use in areas which are frequently impinged by Water.

These and other objects of the invention will be more readily apparent when considered in relation to the preferred embodiments as set forth in the accompanying detailed description and shown in the accompanying drawings in which:

FIG. 1 is a perspective view of a bathtub enclosure constructed in accordance with the principles of the present invention.

FIG. 2 is a perspective view of the inventive wallboard prior to installation in the enclosure shown in FIG, 1, the dimensional scale of FIG. 2 being reduced as compared to FIG. 1.

FIG. 3 is a perspective view similar to FIG. 2 but showing the wallboard in a different condition than shown in FIG. '2 and more advanced prior to installation in the enclosure shown in FIG. 1.

FIG. 4 is a fragmentary cross sectional view, on an enlarged scale, of the wallboard shown in FIG. 2.

FIG. 5 is a fragmentary sectional view of such wallboard taken on line 55 of FIG. 2.

FIG. 6 is a sectional view similar to FIG. 5 and showing the wallboard after removal of a part shown in FIG. 5.

FIG. 7 is a fragmentary enlarged vertical sectional view through the wall structure shown in FIG, 1 and taken generally along the line 77 thereof.

FIG. 8 is a fragmentary enlarged horizontal sectional view of the wall structure at one inside corner thereof shown in FIG. 1 and taken along line 8-8 thereof.

FIG. 9 is a fragmentary sectional view similar to FIG. 8 of a modified wall construction at an inside corner.

The novel wallboard of the present invention is represented generally by the numeral 10. As shown, it comprises a core panel designated generally at 11. This core panel may be of any suitable composition which will render it nailable. While it may be a sheet of hardboard, it is preferred to employ a paper-covered, set gypsum core as the core panel 11. It is this preferred construction of core panel which is illustrated. Thus the gypsum core is shown at 12 and is covered on all four sides by paper indicated at 13 which is bonded to the gypsum core in the well known manner.

Regardless of the composition of the core panel, it is preferred to preform it to have an elongated, generally rectangular outline in plan and cross section. Thus the paper-covered, gypsum core panel illustrated has a flat front side or surface 14,-a flat rear side or surface 15 connected to the parallel front surface 14 by an upper fiat edge surface 16 and a lower flat edge surface 18.

In accordance with the present invention,-such core panel 11 is clad, faced or covered over certain surface areas thereof with a water impervious film designated generally by the numeral 19. This film is made of such material and has such a thickness that it will prevent the penetration of water which may contact its exposed surface, through it into the core panel 11. While any suitable material, whether metallic or non-metallic in character, may be used for the film, it is preferred to employ an organic synthetic polymeric thermoplastic. Any such thermoplastic which is water impermeable will be satisfactory but one which is readily adhereable to the core panel and is reasonably economical is preferred, such as polyvinyl chloride. If such thermoplastic material is employed for the film, it is essential that it have a thickness of at least .002 inch so as to eliminate pin holes and provide a sculf and scrub resistant film. A thickness less than this will not provide a suitable water impervious film, albeit water repellant. On the other hand a film of such thermoplastic material exceeding about .005 inch in thickness becomes unnecessarily thick, somewhat inflexible which is undesirable for a reason hereinafter apparent from an explanation of the installation of the wall board, and is also wasteful of the film material and hence uneconomical. The thermoplastic film having a thickness of about .004 inch, where polyvinyl chloride is employed, is preferred.

The water impervious film 19 covers the entire area of the front surface 14 of the core panel, as well as the entire area of at least one of the edge surfaces 16 and 18 of the core panel. It is essential that the film 19 extend onto or overlap the rear or back surface 15 of the core panel for the full length thereof and adjacent the film-covered panel edge surface. It is essential that the extent of film coverage on the back surface 15 be at least fit-inch from the square corner between the back and edge surfaces of the core panel. An overlap onto the core panel back surface 15 of about /2-inch is preferred, as is also the provision of covering both longitudinal edge surfaces 16 and 18 and the marginal portion of the back surface adjacent to each such edge surface. The portion of the water impervious film covering the core panel front surface 14 is represented by the numeral 20, that portion covering the upper edge surface 16 by the numeral 21, that portion covering the lower edge surface 18 by the numeral 22, that portion covering the back surface 15 adjacent the upper edge surface 16 by the numeral 23, and that portion covering the back surface 15 adjacent the lower edge surface 18 by the numeral 24.

The water impervious film 19 including the portions 20-24 may be fabricated and applied to the core panel 11 as individual portions or elements, as long as any joints between such portions are water-tight and the film 19 as a whole provides an outer or exposed continuous barrier to water penetration to the interior of the wallboard. However, it is preferred that the film 19 be formed as a single, continuous covering for the core panel.

The film 19 may be applied to the core panel 11 in any suitable manner, as by spraying, dipping, painting or as a laminate, with or without a backing such as paper. Since a paper-backed film laminate is relatively easy to preform and handle, it is preferred to employ such a laminate and bond it by a suitable adhesive to the desired surface portions of the core panel 11. In any event, it is preferred that the water impervious film 19 adhere to the core 11 over the entire areas of the interfaces therebetween. The exposed surface of the film 19 may be smooth, although it is preferred to emboss the same slightly, effected for example by rolling with a knurled roller (not shown) when applying the film to the core panel. This .gives tooth to the exposed film surface enabling easy transfer of tile adhesive from the spreading tool (not shown) to such film surface.

The core panel 11 may have any thickness desired, say in the range of from Vs to %-inch. Also, while the dimensions of the rectangular outline of the panel may be any desired, it is preferred to provide such wallboard having a width of four feetand a length of eleven feet. This makes the wall board handleable and still of a length adequate to provide an integral wrap-around construction of base wall for a standard bathtub enclosure as hereinafter explained.

Referring to FIGS. 1 and 8, the numeral 25 represents a bathtub having two ends or sides arranged generally at right angles to an intermediate or third side, which sides are to be enclosed by a wall. Any other water receptor such as the pan at the base of a shower stall is contemplated as the equivalent of the bathtub 25. The rim of the recess 26 of the tub 25, or other similar water receptor, has an upwardly facing shoulder 28 from the outer perimetral edge of which along the aforementioned three sides there extends an upstanding integral flange or lip 29. The tub 25 is shown as arranged against suitable wall support means such as nailing members 30. These members 30 are shown as vertically arranged wooden studs arranged at suitable spacing such as 16 inches on center. A row of such studs 30a is provided at one end of the tub, a second parallel row of studs 30b at the other end of the tub and an intermediate row of studs 300 is arranged along the inner longitudinal side of the tub.

The novel wallboard 10 is installed in the following manner for use as a backerboard for wall tile blocks. The horizontal length l of the enclosure end wall section to be supported on the inner edge surfaces of the studs 30a is measured. The similar horizontal dimension for the opposite enclosure end wall section is also determined. Likewise, the horizontal dimension l for the panel enclosure intermediate wall section is measured. A wall board such as 10 is then cut, if required, so that its length is about equal to the sum of the horizontal lengths l l and 1 Actually the wallboard is formed to have a length: equal to the sum of such dimensions l l and 1 less the approximate thickness of the wall board, say one-half inch, for each corner in the wall perimeter. Thus in the enclosure illustrated in FIG. 1 and if one-half inch thick wallboard is being used, the length of such wallboard should be the sum of dimensions l l and 1 less one inch since there are two90 inside corners.

After the wallboard is so determined as to length, the distance 1 is marked on the back of the wallboard, measuring in from the left end of the same as viewed in FIG. 2. The panel is transversely scored across its back surface 15 with the line s This line s extends perpendicularly to the longitudinal edges of the panel of the wallboard and across the full width thereof. It may be made by a knife drawn along a straight edge (not shown), care being taken not to cut through the film 19 covering the front surface 14 of the core panel and the edges and back margins thereof. In a similar manner the dimension Z is laid out inwardly from the other end of the wallboard and a transverse score line s is provided across the back of the core panel.

Following this, a second score line s is provided across the back surface of the core panel and parallel to the score line s and spaced outwardly therefrom by a distance 1. This distance t corresponds to the thickness of the wallboard 10. A similar second score for the score line s being parallel thereto and arranged outwardly thereof by a distance t.

If the core panel 11 is a paper-covered set gypsum slab, the provision of these score lines with a knife followed by a slight flexing of the wallboard thereafter will crack the core panel across the full thickness thereof as represented in FIG. 5 where the grooves g and g correspond respectively to the score lines s and s shown in FIG. 2. Thereafter the strip 11a of core panel between the grooves g and g may be removed so as to provide the gap G which exists between the panel portion 11b and intermediate panel portion 11c, as shown in FIG. 6. These panel portions 11b and are connected by a web portion 19a of film, also shown in FIG. 6.

It will be appreciated that when the strip of core panel comparable to the strip 11a but between the score lines s and s is removed, there will be a web portion 19b of film similar to the film web portion 19a left between the intermediate panel portion 110 and an end panel portion 11d. These film web portions 19a and 19b are shown in FIG. 3 which illustrates the wallboard 10 with the two strips of core panel comparable to the strip 11a removed and with the end portions 11b and 11d folded inwardly toward each other part way, employing the respective film web portions 19a and 19b as hinges.

Preferably, the backerboard end portions 11b and 11d are folded upon the intermediate backerboard portion 110 so'that the film covered faces of these portions oppose each other. Following this, the folded assembly may be tub enclosure with a film covered longi-- tudinal edge of the wallboard arranged horizontally ad-- tub lip 29. The folded wallboard assembly is:

placed into the jacent the positioned so that the film-covered lower edge surface:

thereof opposes and is spaced slightly above the top surface of the lip 29. This spacing is preferably about A- inch. The lower longitudinal edge of the wallboard extends horizontally parallel to the top surface of the lip 29. With the wallboard intermediate portion 110 in this adjusted position, the same is nailed to the studs 30c employing nails 31. The nails 31 are applied at intervals along in the length of the studs, such interval being preferably about eight inches on center.

Following the application of sufficient nails to hold the intermediate wallboard portion 110 on the studs 30c, the wallboard end portions 11b and 110! are successfuly unline 5 is provided.

folded so that their back surfaces engage the support sur faces of the rows of studs 30a and 30b, respectively. These end portions 11b and 11d are similarly secured to the studs by nails 31.

The nails 31 are conventional wallboard nails and as shown typically in FIG. 8 include a shank 32 having a head 33 at one end and a serrated portion 37 at its opposite end. The nails 31 are driven so that the heads 33 are substantially flush with the planar front face of the wallboard, the nail shanks penetrating the water impervious film 19, the paper-covered gypsum core panel 11 and the corresponding stud therebehind. By driving the nails so that their heads are flush, it has been found that a water-tight seal between the film and the nail is provided, the portion of the film surrounding the nail shank and immediately under the nail head serving as a gasket.

Referring to FIG. 8, it will be seen that the film portion 19a between the wallboard portions 11b and 110 forms a loop, fold or pleat arranged in the space 34 left at the inside corner between the portions 11b, 11c and the adjacent studs 30a and 300. Since this loop, fold or pleat of film 19a and its counterpart 19b are severally continuous vertically across the wallboard and bridge the respective joints between the panel portions 11b, 11c and 11d, and with the portions of the film 19 adhering to the front surfaces of these panel portions, the backerboard installation is provided with a continuous water impervious front surface over the entire exposed are-a of the backerboard.

To this backerboard front surface, wall tile blocks, such as ceramic tile represented typically and individually by the numeral 35, may be suitably mounted, as shown in FIGS. 1 and 7. While the tile blocks may be mounted on the base wall provided by the backerboard in any suitable manner, application by a suitable water-proof adhesive is preferred. Referring to FIG. 7, the numeral 36 represents a suitable water-proof tile adhesive which has been previously coated or combed on the exposed front face of the film 19 and adhering thereto. This adhesive bonds the tile blocks 35 to the base wall, including the lower row of tile blocks one of which is illustrated at 35 in FIG. 7. It is to be noted that the lower row of tile blocks overlaps the upstanding tub lip 29 and is frontwardly spaced therefrom, and that the adhesive 36 terminates adjacent the lower longitudinal edge surface of the backerboard. Preferably a continuous bead 38 of tile adhesive is placed, before application of the lower course of tile blocks, between such blocks and the front face of the tube lip 29. Also, the joint between the lower edges of the bottom row of tile blocks and the top shoulder 28 is preferably filled in with caulking or grout as indicated at 39.

It will thus be seen that the lower longitudinal edge of the backenboard 10 when mounted on the wall and faced with tile in the manner just described, is out of contact with the tub lip 29. Thus should be the caulking or grouting 39 fail as well as the seal bead 38, so that water could work up onto the top edge surface of the tub lip 29, there would still be no contact between such water and the lower edge surface of the backerboard 10. Even should there be, the wrap-around of the film 1-9 onto the back surface of the core panel 11, as represented by the film portion 24, will guard against water working upwardly by capillary action or otherwise into wetting contact with the core panel 11. Should the grouting which is normally placed between the joints of adjacent tile blocks 35 fail or erode away so as to allow water to penetrate the wall structure, it will be seen that this water meets a barrier when it engages the continuous film 19 protecting the core panel 11.

In many cases, a four-foot piece of the inventive film clad walboard arranged above the tub lip 29 will be sufficient. However, if desired another strip of similar film clad wallboard may be placed above the upper edge surface of the backerboard 10 shown in FIG. 7 to provide the height of water impervious base wall construction desired. As an alternative construction, a conventional paper covered, set gypsum core wallboard piece of the desired width and unprovided with a water impervious film, may be arranged edge to edge with the inventive wallboard 10. Whether of a water pervious or impervious construction, such auxiliary panel is fragmentarily and schematically illustrated at 40 in FIGS. 1 and 7. Regardless of the specific type of panel 40, the horizontal joint bet-ween it and the lower inventive wallboard 10 is covered by a suitable waterproof tape 41 having a preferred width of 2 inches and preferably of a pressure sensitive plastic type, which is applied so that about half of the width of such tape overlaps each of these adjoining wallboards.

Instead of applying the inventive backerboard in the manner described hereinabove, the same may be applied in three discrete pieces, an intermediate piece or section of which is shown in FIG. 9 at 11c and one end piece or section at 11b. The open joint 42 at the inside corner between the sections 11b and 11c is shown as covered by a strip of water-proof tape 43 which is preferably the same type as the tape 41. This tape 43 is also applied so that about half of its width overlaps each of the sections 11b and While the inventive backerboard illustrated is shown as having both of its longitudinal edge surfaces covered with water impervious film, it is essential only that one of these edges be film-covered. Where such is the case, it is important that when installing the wallboard as a hackerboard for tile blocks, that the film-covered edge be at the bottom of the panel as it is applied with its major dimension running in a horizontal direction, opposing and preferably spaced from the top surface of the tub lip 29 as previously explained. -As a practical matter, it is preferred to cover both longitudinal edges of the wallboard with the water impervious film so that a workman cannot accidental-1y invert the panel and place an unprotected or film-uncovered edge adjacent the tub lip.

In the means for supporting the backerboard 10, appropriate blocking, headers or supports would be provided to support plumbing fixtures such as faucets, water spout and shower head pipe and to receive soap dishes, grab bars, towel racks and similar items as may be desired. None of these fixtures or items have been illustrated in the drawing. All openings in the base wall, such as areas of exposed gypsum core around pipes, fixtures, etc., would be taped with a water impervious tape such as 41 and 43 and caulked flush to the front surface of the base wall with water resistant ceramic tile adhesive or the like prior to application of the surfacing material such as the tile blocks 35.

With further reference to the support means for the backerboard 10, it is contemplated that such means may include a stud or panel construction. If studs are employed they may be wooden as shown, or metal. In either case, the means for securing the backerboard 10 to the support means may include fasteners such as nails, screws and the like which penetrate the backerboard and underlying support element, or of a non-penetrab le type such as adhesives, mechanical clips and the like.

While the installation of the inventive wallboard has been described with particular reference to a bathtub enclosure, it will be apparent to those skilled in the art that the same technique can be employed for other types of enclosures such as shower stalls or the like. As used in the ensuing claims, the term water receptor is intended to encompass not only a bathtub but a shower stall base or equivalent water receiving member.

When referring to a water impervious film in the preceding description and ensuing claims, it is to be clearly understood that a film which is impervious to water in a liquid state is intended, and not a film which may serve merely as a barrier to water in a vaporous state but 7 be ineffective in preventing the penetration of water in aliquid state.

From the foregoing, it will be seen that the embodfiments of the wallboard and wall construction illustrated .and described, and the method of wall construction described, accomplishes the various objects stated. Inasmuch as various modifications of the wallboard and wall :structure embodying the same and method of constructfing such wall structure, may occur to those skilled in the 'art, the scope of the invention is to be measured by the appended claims.

What is claimed is:

1. A wallboard for backing Wall tile blocks forming a finished wall surface frequently contacted by water such as in bathtub enclosures and shower stalls, said wallboard comprising an elongated generally rectangular core panel including a set gypsum core enclosed on its two faces and two longitudinal edges with paper, and a water impervious film firmly adhered to said paper and extending throughout the extent of a first of said faces and at least one of said edges and extending at least partway onto the second of said faces adjacent said one ofsaid edges throughout the length of said panel.

2. A wallboard for backing Wall tile blocks forming a finished wall surface frequently contacted by water such as in bathtub enclosures and shower stalls, said Wallboard comprising an elongated generally rectangular core panel including a set gypsum core enclosed on its two faces and two longitudinal edges with paper, and a water impervious film firmly adhered to said paper and extending throughout the extent of a first of said faces and at least one of said edges and extending at least fit-inch onto the second of said two faces adjacent said one of said edges'throughout the length of said panel.

3. A wallboard for backing Wall tile blocks forming a finished wall surface frequently contacted by water such as in bathtub enclosures and shower stalls, said wallboard comprising a core panel having an elongated, generally rectangular outline in plan and cross-sectio-n and including a set gypsum core enclosed on its two flat side surfaces and two flat longitudinal edge surfaces with paper, and a single continuous and imperf-orate thermoplastic film of from .002 to .005 inch thick adhered to said paper and covering the entire areas of one of said side surfaces, at least one of said edge surfaces and extending, at least 4-inch onto the other of said side surfaces adjacent said one of said edge surfaces for the length of said panel.

4. A wallboard for backing Wall tile blocks forming a finished wall surface frequently contacted by water such as in bathtub enclosures and shower stalls, said wallboard comprising a core panel having an elongated generally rectangular outline in plan and cross-section and including a set gypsum core enclosed on its two flat side surfaces and two fiat longitudinal edge surfaces with paper, and a single, continuous and imperf-orate thermoplastic film of from .002 to .005 inch thick adhered to said paper and covering the entire areas of one of said side surfaces, both of said edge surfaces and extending about /2-incl1 onto the other of said side surfaces adjacent each of said edge surfaces for the full length of said panel, said film being adhered to said panel over the entire areas of the interfaces therebetween.

References Cited by the Examiner UNITED STATES PATENTS 1,556,575 10/1925 Armstrong 161-103 1,690,253 11/ 1928 Schumacher 161-103 1,819,345 8/1931 Thurman -534 1,870,439 8/1932 Bi-rdsey 161-103 2,031,900 2/1936 Miller 161-104 2,154,143 4/1939 Whelan 156-216 X 2,246,514 6/1941 Hardy 50-534 2,323,299 7/1943 Craig 161-44 X 2,483,888 10/1949 Danielson 50-74 2,677,268 5/1954 Hobbs 50-74 2,705,522 4/1955 Kamborian 156-216 X 2,725,324 11/1955 Holes 156-277 X 2,742,724 '4/ 1956 Fleiss 161-43 2,998,501 8/1961 Edberg et a1 156-79 X 3,034,944 5/1962 Chipman 161-254 3,226,284 12/1965 Curtis 161-44 3,265,547 8/1966 Selbe 156-85 OTHER REFERENCES Modern Plastics (pp. 164 and 165 cited), June 1954.

EARL M. BERGERI, Primary Examiner.

HENRY C. SUTHER, Examiner. H. F. EPSTEIN, Assistant Examiner. 

1. A WALLBOARD FOR BACKING WALL TILE BLOCKS FORMING A FINISHED WALL SURFACE FREQUENTLY CONTACTED BY WATER SUCH AS IN BATHTUB ENCLOSURES AND SHOWER STALLS, SAID WALLBOARD COMPRISING AN ELONGATED GENERALLY RECTANGULAR CORE PANEL INCLUDING A SET GYPSUM CORE ENCLOSED ON ITS TWO FACES AND TWO LONGITUDINAL EDGES WITH PAPER, AND A WATER IMPERVIOUS FILM FIRMLY ADHERED TO SAID PAPER AND EXTENDING THROUGHOUT THE EXTENT OF A FIRST OF SAID FACES AND AT LEAST ONE OF SAID EDGES AND EXTENDING AT LEAST PARTWAY ONTO THE SECOND OF SAID FACES ADJACENT SAID ONE OF SAID EDGES THROUGHOUT THE LENGTH OF SAID PANEL. 